Premature ejaculation results from partners' mismatch: development and validation of index of intra-vaginal ejaculation latency time.

Mismatch of partners in premature ejaculation (PE) regarding intra-vaginal ejaculation latency time (IELT) is usually neglected. Here we proposed the concept and evaluated the use of index of IELT (IIELT) as an objective diagnostic tool for PE. Data from 103 self-reporting PE patients and 59 normal controls were collected. The expected IELTs of both the male and female partners were provided by each participating couple in two questionnaires. IIELT=stopwatch IELT/(1/2 the male's expected IELT+1/2 the female's expected IELT). The stopwatch IELTs were 1.74±1.4 min (PE group) and 14.45±11.0 min (control group), P<0.05. The expected IELTs were 15.65±8.7 min (men) and 14.16±6.9 min (women) in the PE group, and 21.3±16.1 min (men) and 20.04±13.47 min (women) in the control group, P<0.05. The calculated IIELTs were 0.14±0.12 (PE group) and 0.83±0.60 (control group), P<0.05. The best cut-off point was 0.658, the Youden index was 0.652, sensitivity was 0.991, specificity was 0.661, positive predictive probability was 83.46% and negative predictive probability was 97.6%. We concluded that IIELT was an integrated measurement of the couples' sexual equilibrium and demonstrated that it provided a simple and objective screening indicator for diagnosing self-reported PE.